The present invention relates generally to electrical energy sources and more particularly, but not by way of limitation, to interconnectible battery packages for a down-hole tool used in an oil or gas well. The present invention also relates to a method of assembling such an energy source.
The need for electrical energy sources is, of course, widespread. In particular, battery packs or other portable, self-contained electrical power sources are needed for all types of portable electrical apparatus such as portable televisions, radios and video recorders. One other specific usage is with electrical downhole tools, such as a downhole pressure and temperature gauge or a perforating gun, used in making, completing and producing oil and gas wells. It is to this last-mentioned specific need that the present invention is particularly addressed; however, it is contemplated that the present invention can be adapted for more general usage applicable to a variety of other types of electrical apparatus.
Prior electrical energy sources designed for downhole tools have utilized electrical connections that are difficult to use or that are unreliable in particular applications. Such designs have included one or more batteries hard-wired to the circuit to be energized, thereby making it difficult to replace batteries and thereby placing capacity limitations on how long the circuit can be energized. Other designs have used mechanical connections, such as by means of banana jacks or set screws, which are more readily interchangeable than the hard-wired designed; however, these mechanical connections have been found to provide unreliable mechanical, and consequently unreliable electrical, connections, at least in certain applications. Some designs have included a number of batteries or cells linearly arranged in a tube, in a manner analogous to batteries in a flashlight; however, such arrays have not been readily and selectably connectibel in both series and parallel configurations with additional tubes of batteries.
Although such prior designs have been useful within their limitations, there is the need for an improved electrical energy source that overcomes the aforementioned shortcomings. That is, there is the need for an improved electrical energy source that can be used in a variety of tools and that can be readily connected to and disconnected from them through positive, reliable mechanical connectors. Such a source should be packaged in a uniform nature so that it is readily interchangeable and interconnectible with other ones of a similar design. Such interconnectability should also allow two or more packages to be connected either in electrical series or in electrical parallel or a combination of the two.
Of particular significance for the specific application in combination with a downhole tool, but also of general value, is the need for such a source to be compact, and relatively simply but sturdily constructed. Because significant forces can be encountered in a downhole environment, for example, such as from a perforating gun with which the present invention is contemplated to be useful, the electrical conductors within the source should be configured to deform in response to such forces without breaking the electrical continuity.